SHANGHAI – As Jews around the world observe the weeklong festival of Passover, a solitary pair in Shanghai are believed to be all that's left of a tide of Jewish immigrants that once filled the bustling Chinese city.

The streets of Shanghai teemed with 20,000 or more European Jews in the first half of the 20th century, many fleeing persecution in Russia or Nazi Germany.

Sara Imas and her son, Jerry, the last remnants of that era, both live in Shanghai today with their Chinese spouses. But only Sara is celebrating Passover this year — 28-year-old Jerry is not a practising Jew.

“He's completely Chinese,” said Imas, who was brought up in Shanghai by her Chinese mother and Jewish father who came here from Russia in 1939.

“But I'll be celebrating it with other Jews, many of them visiting from Russia. People are bringing the special ingredients and dishes from abroad, like the unleavened bread.”

Imas, now in her 50s, and her son are the last known descendants in Shanghai of a former community of Jewish European exiles, according to the Israeli consulate.

That community was more than 20,000 strong at its height in 1943 when Japan forced all the city's Jews to move into a ghetto in the area now known as Hongkou in the north of the city.

Nearly all of them left following Germany's defeat in 1945, the founding of the state of Israel in 1948, and the creation of the communist People's Republic of China a year later.

Imas herself eventually went to Israel, where she ran a business selling Chinese spring rolls. She later returned to Shanghai, and is now the China representative for an Israel-based diamond company.

But she acknowledges the occasional identity crisis as she – like many others of mixed parentage – tries to reconcile her Jewish and Chinese backgrounds.

“As for me, I am nobody's and I am neither. I pray and go to synagogue here but this is somehow not my hometown,” says Imas, who is fluent in both Chinese and Hebrew.